MEXICO CITY — The U.S. government finally released the first part of a $400 million aid package Wednesday to support Mexico's police and soldiers in their fight against drug cartels.

The money comes at a critical time: Mexico's death toll from drug violence has soared above 4,000 so far this year, and drug-related murders and kidnappings are spilling over the U.S. border as well.

U.S. Ambassador Tony Garza formally released $197 million at a signing ceremony in Mexico City. The rest will be disbursed throughout the year.

Garza said the Merida Initiative aid will enable the United States and Mexico to work more closely, sharing information on the cartels in real time.

But many questions remain about the direction of this drug war, and both Mexico and Colombia, where 90 percent of U.S.-bound cocaine is produced, worry they'll be handcuffed by concerns about human rights and corruption once Barack Obama is president.

"If the United States strips us of those resources, what will be done? Where will they come from?" Andres Pastrana asked in an Associated Press interview. The former Colombian president worked with U.S. President Bill Clinton to launch Plan Colombia, which has spent more than $6 billion in U.S. aid since 2000 to fight drug trafficking and leftist rebels.

Corrupt cops
The aid to Mexico — which includes no cash — includes helicopters and surveillance aircraft, airport inspection equipment and case-tracking software to help police share real-time intelligence. It also supports Mexican efforts to weed out corrupt police, improve the judicial system and protect witnesses.

Most of it, however, will go to notoriously corrupt police forces and the same military whose soldiers have tortured, raped and killed innocent civilians while battling the cartels, according to Mexico's National Human Rights Commission. President Felipe Calderon himself said more than half of state and local police can't be trusted, and federal ranks are rife with corrupt officers.

The U.S. government has stood by Calderon. But Anthony Placido, the U.S. Drug Enforcement Administration's intelligence chief, acknowledged the dangers.

"Law enforcement work anywhere in the world, and certainly in Mexico, can be perilous," Placido said in October when asked whether Mexican corruption has imperiled U.S. agents. "Is it dangerous? Absolutely."

Operation Clean House
After both nation's lawmakers approved the money this summer, Mexico went public with Operation Clean House, which ensnared a dozen high-ranking police officials, including the former drug czar, on allegations of spying for the powerful Sinaloa cartel.

Colombia has been cleaning house as well: A week before Obama's election, President Alvaro Uribe fired 20 officers — including three generals and four colonels — for negligence in the biggest-ever purge of Colombia's military. On Nov. 4, the army commander resigned. Uribe also reversed his resistance to U.N. monitoring, saying he would assign a human rights ombudsman to every battalion.

"The United States is a supremely important ally," Colombian armed forces chief Gen. Freddy Padilla told the AP. "But it's an ally that doesn't provide aid and support blindly."

Colombia places almost no restrictions on U.S. support, allowing U.S. soldiers and drug agents to operate freely in its territory. But Mexicans have always chafed at U.S. military aid, and Calderon's administration objected to human rights restrictions proposed by U.S. lawmakers, who ultimately dropped most of the conditions.

The help still comes with some strings: The last 15 percent won't be released until the State Department confirms Mexico is meeting human rights and police corruption goals.

Washington has been unwavering in its support of Calderon's drug fight, even as top members of his security Cabinet fell in the corruption scandal. Obama also said Central America should get more than the $65 million in aid it is getting as part of the Merida Initiative. And while Obama has frequently criticized Colombia's human rights record, he pledged his full support for Uribe's fight against the leftist Revolutionary Armed Forces of Colombia, which sustains its rebellion with cocaine profits.

But the United States is taking a hard look at how it fights this drug war — starting with the U.S. money and guns that sustain the cartels. The Brookings Institution estimates that 2,000 guns enter Mexico from the United States every day, and many Latin American nations complain that U.S. drug consumption is ultimately responsible for the violence.

'Responsibility'
"The U.S. has to go after the flow of guns and bulk cash and stolen vehicles that go from north to south over our southern border," one of Obama's top Latin America advisors, Dan Restrepo, told The AP. "It's our responsibility to do far more than what we're doing to cut off those flows."

The mostly military nature of the aid also is being examined after the U.S. Congress's research arm reported that Plan Colombia has failed to meet its goal of halving illegal drug production in Colombia, and coca cultivation increased 27 percent last year. Vice President-elect Joe Biden commissioned last month's report as Senate Foreign Relations chairman.

Democrats in Congress already shifted more than $100 million of Colombia's aid to nonmilitary purposes, such as strengthening the judicial system and responding to the world's worst internal refugee crisis after Sudan.

Colombia's military, which has nearly doubled in size under Uribe, worries of more cuts to come.

"It would be an error to deprive of aid a government with a clear democratic conviction and a military that is infinitely respected by the Colombian people," Padilla said.

Obama, however, argued during the campaign that only a regional, multilateral approach can discourage cartels from crippling governments through corruption and intimidation: "It's time to work together to find the best practices that work across the hemisphere, and to tailor approaches to fit each country," Obama said.